Bayesian comparison of test-day models under different assumptions of heterogeneity for the residual variance: the change point technique versus arbitrary intervals

Test‐day milk yields from Spanish Holstein cows were analysed with two random regression models based on Legendre polynomials under two different assumptions of heterogeneity of residual variance which aim to describe the variability of temporary measurement errors along days in milk with a reduced number of parameters, such as (i) the change point identification technique with two unknown change points and (ii) using 10 arbitrary intervals of residual variance. Both implementations were based on a previous study where the trajectory of the residual variance was estimated using 30 intervals. The change point technique has been previously implemented in the analysis of the heterogeneity of the residual variance in the Spanish population, yet no comparisons with other methods have been reported so far. This study aims to compare the change point technique identification versus the use of arbitrary intervals as two possible techniques to deal with the characterization of the residual variance in random regression test‐day models. The Bayes factor and the cross‐validation predictive densities were employed for the model assessment. The two model‐selecting tools revealed a strong consistency between them. Both specifications for the residual variance were close to each other. The 10 intervals modelling showed a slightly better performance probably because the change point function overestimates the residual variance values at the very early lactation.     

No major effect of the leptin gene polymorphism on porcine production traits

Porcine leptin gene (LEP) and its association with production traits was analysed in the Polish Large White (PLW, n = 135), Polish Landrace (PL, n = 120) and synthetic line 990 (L990, n = 184). Two fragments of exon 3 of LEP were studied with the use of RFLP and SSCP techniques. The frequencies of C allele for the T3469C polymorphic site were 0.11, 0.10 and 0.11 in PLW, PL and L990, respectively. Phenotypic data were collected for the average daily weight gain, the feed conversion ratio, the weight of abdominal fat, backfat thickness (five measurements), intramuscular fat, meat content, loin weight, loin muscle area, ham weight and ham cut weight. The contrasts between TT and TC genotypes at the T3469C polymorphic site were estimated in the unitrait Animal Model with genotype at the RYR1 locus included. The lowest p values occurred for association test between T3469C polymorphism and intramuscular fat content in PLW (0.26 ± 0.14%, p = 0.05) and loin weight in L990 (?0.32 ± 0.13 kg, p = 0.01). We conclude that the detected associations are population‐specific and the analysed polymorphism of the LEP gene does not contribute directly to genetic variability of growth and carcass traits in pigs.     

FC-17 Cutaneous papillomatosis and carcinomatosis in the highly endangered Western Barred Bandicoot

Newcastle disease virus (NDV) has antineoplastic and immunostimulatory properties, and it is currently being clinically tested in anticancer therapy. In order to analyse the immunostimulatory effects of NDV on bovine papillomatosis, we inoculated 14 cows subcutaneously with an attenuated vaccine containing the LaSota strain of NDV (LS-NDV). Four cows with papillomatosis served as controls. Serum samples were collected from each animal 1 h preinoculation and 7 and 21 days postinoculation. In inoculated cows on days 7 and 21, the mean antibody titres were log₂ 2.43 ± 0.92 and 5.57 ± 0.72, respectively, by haemagglutination inhibition, and the mean levels of TNFα were 5.80 ± 4.19 and 5.39 ± 2.66 ng/mL, respectively, by WEHI-164 cytotoxicity assay. Significant differences between inoculated and control animals were evident for antibody titres on day 21 and clinical scores on day 60. A correlation was evident between the TNFα activities and clinical scores on day 21. The clinical observations at day 60 showed that the papillomas in five cows had completely resolved (36%), one animal had no alterations on clinical appearance of the tumour (7%), and papillomas in eight cows had regressed (57%). In conclusion, these results demonstrated that inoculation of LS-NDV vaccine stimulates an antibody response and a limited increase in TNFα activity and may enhance clinical recovery in bovine papillomatosis.
Funding: Scientific Research Council of Akdeniz University.     

Monitoring response to aminobisphosphonate therapy in canine osteosarcoma using dual energy x‐ray absorptiometry (dexa)

Introduction: Palliative therapy is essential to improve the quality of life of dogs with osteosarcoma (OSA), when definitive therapy is not considered a valid option. Bisphosphonates, a novel class of antiosteoclastic drugs, are widely used in humans for several painful osteolytic conditions. Dual energy x‐ray absorptiometry (DEXA) is recognized as a reliable tool to measure bone mineral density (BMD), and to monitor treatment response to bisphosphonates in humans. A prospective evaluation of pamidronate, an injectable aminobisphosphonate, is ongoing in dogs with appendicular OSA. The potential value of DEXA for objective evaluation of BMD variations with palliative therapies is concurrently being assessed. Materials and Methods: Dogs with naturally occurring appendicular OSA treated with pamidronate constitute the patient population. A DEXA scan (QDR‐4500 W, Hologic, Bedford, MA) is performed on day 0 (baseline) and on every treatment day with pamidronate thereafter (every 28 days). For each dog, a whole body scan is performed, followed by a scan of the tumor, and contralateral normal bone. Three regions of interest are subsequently analyzed for BMD changes in tumor and normal bone. Statistical analysis was performed using Student t‐test and paired t‐tests, with significance being set at p < 0.05. Results: Nineteen dogs have been enrolled to date. Seven responders and 6 non‐responders have suitable data for analysis. A significant difference is observed (p = 0.04) between tumor BMD variations of responders and non‐responders at day 28 (mean variations +18.0% and ?4.6% respectively). The changes at day 28 are significant only in the responders (p = 0.038 vs p = 0.05 in non‐responders). When BMD of tumor and normal bone at day 84 is compared to day 0 in six responders, only tumor had a significant increase (p = 0.017 vs p = 0.279, respectively). Conclusions: Objective measurements of response to therapy are essential in pain palliation studies. Increased tumor bone BMD, as obtained by DEXA analysis, may correlate with subjective clinical improvement in pamidronate‐treated dogs with appendicular OSA.     

Cardiac troponin I in canine patients with lymphoma and osteosarcoma receiving doxorubicin: comparison with clinical heart disease in a retrospective analysis

The cumulative cardiotoxicity that occurs as a result of doxorubicin chemotherapy is irreversible and can affect both quality and quantity of life for the cancer patient. Cardiac troponin I (cTnI) is a sensitive and specific marker of cardiomyocyte death. The purpose of this retrospective study was to evaluate serum concentrations of cTnI in dogs with lymphoma or osteosarcoma given doxorubicin chemotherapy, and with known cardiac outcome, based on a minimum assessment by physical examination and thoracic radiography. Serum samples were also available for cTnI measurement from seven healthy dogs given intracoronary doxorubicin. Serial serum samples obtained before, during and after doxorubicin chemotherapy showed increased cTnI concentrations in some clinical patients following chemotherapy (P = 0.0083 compared to baseline), but this did not correlate with clinical signs of cardiomyopathy. In dogs that subsequently developed cardiomyopathy however, serum cTnI concentrations were elevated before clinical signs became evident (confirmed with echocardiography).     

P‐81 A retrospective study of equine sarcoidosis

The purpose of this retrospective study was to evaluate six cases of equine sarcoidosis for initial presenting symptoms, response to therapy and actual outcome. Dermatologists and dermatopathologists from Europe, the United States, Australia and Canada were contacted to obtain these six cases, as this is a rare disease. Signalment, clinical signs, histological findings, clinical management and outcome were determined via a questionnaire and compared to former reports. There was no age or breed predilection, and four of six horses were geldings. Age of onset ranged from 3 months to 17 years. Onset of the disease was insidious or rapid. Interestingly, in five of six cases, scaling began on the trunk (girth and shoulder). Scaling, crusting and alopecia were seen in all six horses. In one horse, clinical signs of systemic disease were reported and included intermittent fever, prescapular lymphadenopathy, depression, poor body condition and nasal discharge. Treatment included phenylbutazone, deworming agents, antibiotics, short‐term low‐dose corticosteroids, and 1–1.5 mg/kg of prednisolone. One horse showed a partial response to trimethoprim and sulfonamide, and five of six went into clinical remission with corticosteroid treatment. Five of six horses were still alive 1 year after diagnosis; one horse was diagnosed <12 months ago. Two horses are in complete remission 4 and 8 years after diagnosis. In both horses, clinical signs recurred after cessation of therapy and went into remission again with reintroduction of treatment. Both of these horses have been in remission for several years without therapy. Funding: Self‐funded.     

Antiviral Effect of Saccharomyces cerevisiaeβ‐glucan to Swine Influenza Virus by Increased Production of Interferon‐γ and Nitric Oxide

The aim of these experiments was to investigate the potential antiviral effect of Saccharomyces cerevisiaeβ‐glucan on the pneumonia induced by swine influenza virus (SIV). Forty colostrum‐deprived 5‐day‐old piglets were randomly divided into four groups of 10. The 20 pigs in groups 1 and 2 were administered Saccharomyces cerevisiaeβ‐glucan orally (50 mg/day/pig; En‐Bio Technology Co., Ltd) for 3 days before SIV infection and those in groups 3 and 4 were given culture medium/diluent alone. Groups 1 and 3 were inoculated intranasally with 3 ml of tissue culture fluid containing 2 × 10⁶ tissue culture infective doses 50% (TCID₅₀)/ml of SIV and those in groups 2 and 4 were exposed in the same manner to uninfected cell culture supernatant. The microscopic lung lesions induced by SIV infection (group 1 pigs) were significantly more severe than those induced by infection in animals pre‐administered β‐glucan (group 3) (P < 0.05). Significantly more SIV nucleic acid was detected in the lungs of pigs experimentally infected with SIV only (group 1) at 5, 7 and 10 days post‐inoculation (dpi) compared with lungs from pigs pre‐administered β‐glucan and infected with SIV (group 3) (P < 0.05). The concentrations of interferon‐γ (IFN‐γ) and nitric oxide (NO) in bronchoalveolar lavage fluid from pigs pre‐administered β‐glucan and infected with SIV (group 3) were significantly higher than for any other group at 7 and 10 dpi for IFN‐γ, and at 5, 7 and 10 dpi for NO (P < 0.05). Saccharomyces cerevisiaeβ‐glucan reduced the pulmonary lesion score and viral replication rate in SIV‐infected pigs. These findings support the potential application of β‐glucan as prophylactic/treatment agent in influenza virus infection.     

Epidemiological Study of Non‐contagious Intramammary Infections in Nine Commercial Dairy Herds following a Staphylococcus aureus Control Programme

Changes in prevalence in intramammary infection, by pathogen type, in herds applying a stringent contagious mastitis control programme was studied. Enrollment of 1651 lactating cows and collection of milk samples was made in this ancillary study to a cohort study of the dynamics of mastitis prevalence after adoption of a strict contagious mastitis control programme that targeted the elimination of mastitis caused by Staphylococcus aureus. Nine commercial dairies in Italy were used. Aseptic collection of milk samples from all lactating cows was performed at the time of enrollment, from all cows within 7–14 days of entering the lactating herd after the date of enrollment, and from all lactating cows at 2, 4, 7, 10 and 14 months after the date of enrollment. Prevalence of intramammary infection by pathogen type was determined from culture of milk samples. Application of the strict contagious mastitis programme did not lead to an increased risk of non‐contagious mastitis. The risk of coliform, environmental streptococcal and coagulase‐negative staphylococcal intramammary infections decreased after adoption of the programme. The data reported herein indicate that the overall risk for any intramammary infections decreases with adoption of a strict contagious mastitis programme, and that such a programme therefore does not necessarily lead to an increase in environmental mastitis.     

A perspective on the measurement of time in plant disease epidemiology

The growth and development of plant pathogens and their hosts generally respond strongly to the temperature of their environment. However, most studies of plant pathology record pathogen/host measurements against physical time (e.g. hours or days) rather than thermal time (e.g. degree-days or degree-hours). This confounds the comparison of epidemiological measurements across experiments and limits the value of the scientific literature.